RO/DI and Phosphates

[skipb]

Does a RO/DI unit remove all the phosphates? I have a SpectraPure 4 stage unit (ELIM/75/RODI) that is a couple years old and I'm trying to figure out if it is time to change the filters. No manual came with the unit so I called SpectraPure and they are sending one. But in the meantime I'm trying to figure out if there should be any phosphates in the ro/di water. I tested it yesterday and had a .2 reading right out of the unit. I this normal?
Thanks,
Skip

 

[ironreef]

Di should remove all po4. and if its .2 its to high. I belive po4 test kits say .03 max. I don't test po4 anymore= its always undetectable in my tank and you can't test for organic po4 anyway so I quit testing for that. Test your alk it should measure 0. But if you ran it for a few years i would change filters. Or if you didn't run it you could have dried out you membrane= need new one new filters and di.

 

[kris walker]

Good question, and good to know info Ironreef. I had the same problem a couple of weeks ago. The RO/DI unit I was getting water from was giving out water with 0.2-0.3 ppm phosphate. I guess the owner has not got aroudn to changing the membrane.
sam

 

[ironreef]

fwiw membrane depending on the type will only remove @95% impurity= you still can have po4 depending on your water. The ro works =sedimate-carbon filter -membrane= @95% then through the di= @99% pure. The ro is just to make the di last longer.